Inherent addressing
Here the address is already built in to the instruction i.e. inherent to the code
ABA ; Add A to B and store the answer in A
Simple programs using the 68HC11 language
This section of functions include instructions such as ALU functions, simple movement and logically operations .Let us consider the addition of two 8 bit numbers
Program One: Data is immediate
LDAA #$fe ; Load hex fe into accumulator A
ADDA #$1 ; Add 1 hex to A i.e total = ff hex
Program two: Direct addressing and extended addressing
Assume the data is stored at the following Ram address
Address Data
501 fe Number One
502 01 Number Two
503 Result
LDAA $501 ;Load fe from address 501 into A
ADDA $502 ;Add 01 from address 502 into A
STAA $503 ;Store the answer ff at address 503
Program three: Index addressing
Assume the data is stored at the following Ram address
Address Data
500 fe Number One
501 01 Number Two
502 Result
LDX #$500 ;Load IX with 500 base address
LDAA $0,X ;Load data from 500 + 0 into A i.e fe
ADDA $1,X ;Add data from 500+1 to A i.e ff
STAA $2,X ;Store A at address 500+2